Don't mention right associativity

As suggested by @HansOlsson.

Co-authored-by: Hans Olsson <HansOlsson@users.noreply.github.com>

chapters/operatorsandexpressions.tex

@@ -30,7 +30,6 @@ \section{Operator Precedence and Associativity}\label{operator-precedence-and-as
 Precedence group associativity is used to determine the implicit subexpression structure when operators belong to the same group of equal precedence.
 Left associativity means that subexpressions are formed from left to right.
 For example, left associativity of binary additive operators means that \lstinline!1 - 2 - 3! is implicitly structured as \lstinline!(1 - 2) - 3!.
-Right associativity means forming subexpressions from right to left, but there is no precedence group with this associativity in Modelica.
 A precedence group may also be non-associative, meaning that there is no implicit subexpression structure defined based on associativity.
 For example, non-associativity of relational operators means that \lstinline!1 < 2 < 3! is an invalid expression.
 Note that the operators don't need to be identical for associativity to matter; also \lstinline!1 == 2 < 3! is invalid, and \lstinline!1 - 2 + 3! is implicitly structured as \lstinline!(1 - 2) + 3!.